The radiation valley and exotic resonances in Wγ production at the LHC

Abstract

Abstract The tree-level partonic angular distribution of Standard Model Wγ production possesses a feature known as the Radiation Amplitude Zero (RAZ) where destructive interference causes the cross section to vanish. At the proton level the exact cancellation disappears, however, one can find a dip in the central region of the angular distributions, here called the Radiation Valley (RV). In this paper, we show how the sensitivity for W(ℓv)γ resonances can be significantly improved if one focuses on events in the RV region. Using this technique, we find that the LHC could probe a larger range of resonance masses, equivalent to increasing the luminosity by a factor of 2–3 over conventional searches. The exact increase depends on the spin of the Wγ resonance and exactly how it couples to electroweak gauge bosons.